Raney A K, Milich D R, McLachlan A
Department of Molecular and Experimental Medicine, Research Institute of Scripps Clinic, La Jolla, California 92037.
J Virol. 1989 Sep;63(9):3919-25. doi: 10.1128/JVI.63.9.3919-3925.1989.
The regulatory DNA sequence elements that control the expression of the hepatitis B virus major surface antigen gene in the hepatoblastoma cell line HepG2 were analyzed by using transient transfection assays. In this system, the hepatitis B virus enhancer increases transcription from the surface antigen promoter approximately twofold. The promoter elements regulating the expression of this gene are within a 200-nucleotide sequence located immediately upstream of the transcription initiation sites. The promoter consists of an 85-nucleotide distal element which increases transcription from the surface antigen gene by two- to fourfold and a proximal element of approximately 115 nucleotides which is essential for transcriptional activity. The proximal and distal promoter elements were shown to bind factors present in HepG2 nuclear extracts, which is consistent with the regulatory role demonstrated for these sequences. The regulatory role of these promoter sequences in the hepatocellular carcinoma cell lines PLC/PRF/5 and Hep3B was also demonstrated, indicating similar transcriptional regulation of the surface antigen gene in each of these differentiated hepatoma cell lines.
通过瞬时转染实验分析了控制肝癌细胞系HepG2中乙肝病毒主要表面抗原基因表达的调控DNA序列元件。在该系统中，乙肝病毒增强子使表面抗原启动子的转录增加约两倍。调控该基因表达的启动子元件位于转录起始位点上游紧邻的200个核苷酸序列内。启动子由一个85个核苷酸的远端元件和一个约115个核苷酸的近端元件组成，远端元件使表面抗原基因的转录增加两到四倍，近端元件对转录活性至关重要。近端和远端启动子元件可与HepG2核提取物中的因子结合，这与这些序列所显示的调控作用一致。这些启动子序列在肝癌细胞系PLC/PRF/5和Hep3B中的调控作用也得到了证实，表明在这些分化的肝癌细胞系中表面抗原基因存在相似的转录调控。
